Genomics is rapidly changing treatment paradigms for cancers, obligating oncologists to have good genomics knowledge. Through this survey, we aimed to assess the current understanding of cancer genomics among UK oncologists. MethodsWe conducted a web-based nation-wide self-assessment survey of the cancer genomics knowledge of UK clinical and medical oncology trainees and consultants. ResultsIn total, 150 oncologists (81 consultants and 69 trainees) responded, representing 10% of UK oncologists.Formal training in genomics had not been received by 38.7% of oncologists and 92.7% identified a need for additional genomics training.In total, 71.3% self-reported to have good knowledge of defining somatic and germline mutations, falling to 35.3% for understanding principles of gene expression and regulation. Knowledge of cancer-predisposing syndromes was highest for Lynch syndrome (40.7% good knowledge) and lowest for multiple endocrine neoplasia (14.0% good knowledge).Overall, 49.0% of respondents had consented patients for germline testing, but 80.7% reported a lack of training in genetic counselling. Conclusion Large knowledge gaps have been identified through this survey, highlighting the need for incorporation of improved formal training in cancer genomics for consultants and trainees, with